Genetic and epigenetic regulation of phenotypic variation in invasive plants – linking research trends towards a unified framework

Abstract

Phenotypic variation in the introduced range of an invasive species can be modified by genetic variation, environmental conditions and their interaction, as well as stochastic events like genetic drift. Recent studies found that epigenetic modifications may also contribute to phenotypic variation being independent of genetic changes. Despite gaining profound ecological insights from empirical studies, understanding the relative contributions of these molecular mechanisms behind phenotypic variation has received little attention for invasive plant species in particular. This review therefore aimed at summarizing and synthesizing information on the genetic and epigenetic basis of phenotypic variation of alien invasive plants in the introduced range and their evolutionary consequences. Transgenerational inheritance of epigenetic modifications was highlighted focusing on its influence on microevolution of the invasive plant species. We presented a comprehensive account of epigenetic regulation of phenotypic variation and its role in plant invasion in the presence of reduced standing genetic variation, inbreeding depression and associated genomic events which have often been observed during introduction and range expansion of an invasive alien species. Finally, taking clues from the studies conducted so far, we proposed a unified framework of future experimental approaches to understand ecological and evolutionary aspects of phenotypic variation. This holistic approach, being aligned to the invasion process in particular (introduction-establishment-spread), was intended to understand the molecular mechanisms of phenotypic variation of an invasive species in its introduced range and to disentangle the effects of standing genetic variation and epigenetic regulation of phenotypic variation.

Hypomethylation of the aquatic invasive plant, Ludwigia grandiflora subsp. hexapetala mimics the adaptive transition into the terrestrial morphotype

“…Further investigations involving spatial genetic structure and genomic approaches should help disentangling between those hypotheses. However, even if such fast-terrestrial transition would have emerged from a newly acquired genetically based adaptive capacity hidden in a dominant pattern of isolation-by-distance, it would not exclude an additive, complementary or even dominant epigenetic effect on their phenotypes (Lele et al 2018, Banerjee et al 2019.…”

“…However, different scenarios can be discussed here. The implication of DNA methylation could be causal through the control of gene expression or transposable element activation as well as a downstream marker of changes resulting from genetic changes (Banerjee et al 2019). In addition, our data showed a weak genetic population structuration, but we cannot exclude that the terrestrial morphotype has been selected from the aquatic population with some genetic diversity (for example transposable elements) and become successful in terrestrial conditions.…”

“…Indeed, plant phenotype can reflect past environments of parents or even grandparents due to transgenerational effects as proposed in the clonal plant Trifolium repens (Rendina González et al 2018). There is potential for environment-induced, heritable DNA methylation to exist in addition to other parental effects (Rendina González et al 2018) A future challenge will be to disentangle genetic and epigenetic effects notably for invasive plants (Banerjee et al 2019. One solution concerning clonal invasive plants such as L. grandiflora subsp.…”

“…hexapetala could be to focus on a single clone vegetatively propagated for each morphotype and to develop an epi/genomic strategy in parallel to the creation of genomic resources (genome and transcriptome). Banerjee et al (2019) present an experimental framework for the characterization of the three-way relationship between environmental cue, phenotypic plasticity and epigenetic changes. They recommend also 'combining trait and molecular data and including comparative analysis of fitness functions between native and introduced ranges of a species and explore adaptive differentiation in invaders, while accounting for non-adaptive evolutionary changes'.…”

Applications of Biotechnology for Characterization of Plants and Pests as the Key Components of Plant Protection and Production Strategies: A Review

“…The phenotypic information is derived from the proteins and their functions, different chemotaxonomic markers and a wide range of other expressed features, Whereas Genotypic information is derived from elucidation of DNA/RNA composition and structure or sequence. The comparison or combined use of phenotypic and genotypic methods of characterization have been described for several plants (Ene et al, 2016;Shikha et al, 2019;Wang et al, 2019), pathogens (Popović et al, 2013;Abdellatif et al, 2017), insects (Kharrat et al, 2012;Dutta et al, 2014) and weeds (Banerjee et al, 2019;Kerr et al, 2019).…”